From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Testing and performance measurements of twelve different valve springs.
| Identifier | ExFiles\Box 80\3\ scan0110 | |
| Date | 29th January 1912 | |
| x290 Section 604 REPORT ON VALVE SPRINGS 29.1.12 No. | Hours running | Measurements before | Measurements now | R E M A R K S. ---|---|---|---|--- 1 | 179 1/2 | 3 1/16 | - | No.1 took a permanent set after 30 hours, changed. 2 | 209 1/2 | 3 1/8 | 3 1/16 | " 3 | 209 1/2 | 3 1/16 | " | 4 | 209 1/2 | 3 1/16 | " | 5 | 209 1/2 | 3 11/32 | " | 6 | 209 1/2 | 3 1/16 | " | 7 | 179 1/2 | 3 3/8 | " | Springs broke after 30 hours. 8 | 209 1/2 | 3 3/8 | " | 9 | 177 1/2 | 3 3/8 | " | Springs broke after 32 hours. 10 | 101 1/2 | 3 11/32 | " | Springs broke after 108 hours. 11 | 209 1/2 | 3 1/16 | " | 12 | 209 1/2 | 3 3/8 | " | Copy of report sent to M/Prasin E P H / T23/12. on Exp file. | ||